Saw blade

ABSTRACT

A saw blade includes left and right set teeth which are set in a lateral direction, as viewed in a cutting direction of cutting teeth. The left and right set teeth include dovetail shaped set teeth, each having a tooth tip formed into a dovetail shape gradually enlarged in the lateral direction, respectively; and a straight tooth, which is not set. The straight tooth includes a dovetail shaped straight tooth having a tooth tip formed into a dovetail shape gradually enlarged in the lateral direction. In the straight tooth, inclinations are formed on both of left and right ends at the tooth tip, which is formed into the dovetail shape gradually enlarged in the lateral direction.

TECHNICAL FIELD

The present invention relates to a saw blade and, more particularly, toa saw blade including a dovetail shaped set tooth having left and rightset teeth, which are set on left and right sides and whose tooth tipsare formed into a dovetail shape gradually enlarged in a lateraldirection.

BACKGROUND ART

In conventional manner, in the case where a metallic workpiece, forexample, is cut, saws such as a circular saw and a band saw have beenwidely used in the prior art. A saw blade serving as a cutting tool foruse in the above-described saw is configured such that numerous cuttingteeth for cutting the workpiece are arranged at appropriate pitches.Exemplary types of saw blades include a so-called set tooth type and adovetail shaped set tooth type.

The above-described set tooth is provided with a straight tooth, asviewed in a cutting direction of the cutting teeth, and left and rightset teeth whose tooth tips are set in a lateral direction in order toperform a setting work in the lateral direction. Chattering vibration,noise or the like generated during a cutting work of the workpiece hasbeen coped with by designing an arrangement pattern of the appropriatenumber of straight teeth and the plurality of left and right set teethin any one of various kinds of patterns such as a raker set, a wave setand a straight set or arranging the cutting teeth at unequal pitches.

The above-described dovetail shaped set tooth type is not provided withleft and right set teeth which are set in the lateral direction, but isprovided at each of the cutting teeth with a dovetail shaped chip whichis gradually enlarged in the lateral direction on a tooth tip side,wherein the chip may have various shapes and dimensions, as disclosedin, for example, Japanese Patent Application Laid-open Nos. 10-193219and 2000-317729.

As shown in FIGS. 10A to 10C, a conventional saw blade 101 of the settype includes a blade base 103, which is provided with a straight tooth105 without setting in a lateral direction, as viewed in a cuttingdirection of a workpiece W by means of the saw blade 101, and left andright set teeth 107 and 109, which are set in the lateral direction.With the above-described configuration, the thicknesses of the straighttooth 105 and the left and right set teeth 107 and 109 are equal to thethickness of the blade base 103.

If a setting quantity, that is, a scarf width S of the left and rightset teeth 107 and 109 is small in the above-described saw blade 101, aninclination angle 0 of each of the left and right set teeth 107 and 109becomes small in a vertical direction. Therefore, if respective outsidecorners 107C and 109C of the left and right set teeth 107 and 109 arefinely abraded in a horizontal direction, a vertical dimension H at theabraded portion becomes relatively larger than an abrasion quantity inthe horizontal direction. An inner surface F of a cutting groove formedat the workpiece W is brought into larger contact with the abradedportion at the left or right set tooth 107 or 109.

When the workpiece W is cut by the saw blade 101, the left and right setteeth 107 and 109 are elastically deformed in the lateral direction withthe application of partial force in the lateral direction. As describedabove, when the inner surface F of the cutting groove formed at theworkpiece is brought into larger contact with the abraded portion at theleft or right set tooth 107 or 109, cutting resistance becomes larger,and further, the partial force in the lateral direction exerted on theleft and right set teeth 107 and 109 becomes larger. As a consequence,the saw blade 101 is turned into an unstable state, thereby inducingbreakage or bending.

In view of this, if the inclination angle θ of each of the left andright set teeth 107 and 109 is to be increased by making constant thescarf width S, i.e., a cutting margin in cutting the workpiece W, abending position P, at which the left and right set teeth 107 and 109are bent in the lateral direction, undesirably approaches the toothtips. In this case, since a fine portion in the vicinity of the tip ofthe cutting tooth in the saw blade 101 is deformed in the lateraldirection with application of lateral large force, the tip of thecutting tooth is largely deformed, i.e., crushed, thereby raising aproblem.

In the meantime, the saw blade of the dovetail shaped set tooth type isnot provided with left and right set teeth, which are set in a lateraldirection, but it is generally configured such that a chip having atrapezoidal shape (i.e., a dovetail shape) in cross section is joined toa tip of a straight tooth without setting in the lateral direction.Here, if an inclination angle of a side surface of the chip portion isto be increased, the bottom side of the trapezoid becomes longer,thereby providing an undesirable configuration in which the chip becomeslarger and cutting resistance becomes larger.

The invention has been accomplished to solve the above-describedproblems experienced in the prior art. Therefore, an object of theinvention is to provide a saw blade in which a vertical dimension can besuppressed to a low level in view of a horizontal abrasion quantity atan outside corner of each of left and right set teeth.

DISCLOSURE OF THE INVENTION

In order to achieve the above-described object, a saw blade according tothe invention based on a first aspect provided with numerous cuttingteeth for cutting a workpiece at appropriate pitches, comprises: leftand right set teeth, which are set in a lateral direction, as viewed ina cutting direction of the cutting teeth; each of the left and right setteeth being a dovetail shaped set tooth having a tooth tip, which isformed into a dovetail shape gradually enlarged in the lateral directionin the above-described configuration.

A saw blade according to the invention based on a second aspect furthercomprises: a straight tooth, which is not set in the lateral direction,as viewed in the cutting direction of the cutting teeth; the straighttooth including a dovetail shaped straight tooth having a tooth tip,which is formed into a dovetail shape gradually enlarged in the lateraldirection, in the above-described configuration in the first aspect.

A saw blade according to the invention based on a third aspect furthercomprises: a straight tooth, which is not set in the lateral direction,as viewed in the cutting direction of the cutting teeth; the straighttooth including a bevel-dovetail shaped straight tooth havinginclinations at both of left and right ends of a tooth tip, which isformed into a dovetail shape gradually enlarged in the lateraldirection, in the above-described configuration in the first aspect.

A saw blade according to the invention based on a fourth aspect furthercomprises: a straight tooth, which is not set in the lateral direction,as viewed in the cutting direction of the cutting teeth; wherein in theabove-described configuration, the straight tooth includes a dovetailshaped straight tooth having a tooth tip, which is formed into adovetail shape gradually enlarged in the lateral direction, and abevel-dovetail shaped straight tooth having inclinations at both of leftand right ends of a tooth tip, which is formed into a dovetail shapegradually enlarged in the lateral direction; and a height of thedovetail shaped straight tooth is smaller than or substantially equal tothat of the bevel-dovetail shaped straight tooth in the first aspect.

In a saw blade according to the invention based on a fifth aspect, aheight of each of the left and right set teeth is smaller than orsubstantially equal to that of the straight tooth in any one of thesecond to fourth aspects.

In a saw blade according to the invention based on a sixth aspect, aninclination is formed at an inside corner on a tooth tip side of each ofthe left and right set teeth in any one of the second to fifth aspects.

In a saw blade according to the invention based on a seventh aspect, thecutting teeth are configured by joining a dovetail shaped chip to thetip end of the tooth in a blade base; and the thickness of the chip atthe joint portion is made to be smaller than that of the tip end of thetooth in any one of the first to sixth aspects.

Since the invention provides the configuration in which the left andright set teeth including the dovetail shaped set teeth, each having thetip formed into the dovetail shape gradually enlarged in the lateraldirection, the inclination angle at the side surface of each of the leftand right set teeth with respect to the vertical direction can beincreased by combining the inclination angle of the dovetail shape withthe inclination angle in setting in the lateral direction.

Consequently, it is possible to suppress a vertical dimension to a lowlevel in view of a horizontal abrasion quantity at the outside corner ofeach of the left and right set teeth, thus solving the above-describedproblems experienced by the prior art.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A, 1B and 1C are views explanatory of a saw blade in a firstpreferred embodiment according to the invention;

FIGS. 2A, 2B and 2C are views explanatory of a saw blade in a secondpreferred embodiment according to the invention;

FIGS. 3A, 3B and 3C are views explanatory of a saw blade in a thirdpreferred embodiment according to the invention;

FIGS. 4A, 4B and 4C are views explanatory of a saw blade in a fourthpreferred embodiment according to the invention;

FIGS. 5A, 5B and 5C are views explanatory of a saw blade in a fifthpreferred embodiment according to the invention;

FIGS. 6A, 6B and 6C are views explanatory of a saw blade in a sixthpreferred embodiment according to the invention;

FIGS. 7A, 7B and 7C are views explanatory of a saw blade in a seventhpreferred embodiment according to the invention;

FIGS. 8A, 8B and 8C are views explanatory of the saw blade inmodifications of the seventh preferred embodiment according to theinvention;

FIGS. 9A and 9B are views explanatory of a straight tooth and set teethin a saw blade in modifications; and

FIGS. 10A, 10B and 10C are views explanatory of the configuration of atypical saw blade in the prior art.

BEST MODE FOR CARRYING OUT THE INVENTION

A description will be given below of saw blades in preferred embodimentsaccording to the invention in reference to the attached drawings.

Referring to FIGS. 1A to 1C, a saw blade 1 in a first preferredembodiment according to the invention includes a blade base 3 made of ahighly resilient material such as a spring steel. At the blade base 3are formed numerous cutting teeth for cutting a workpiece (which is notshown in FIGS. 1A to 1C) at appropriate pitches. The cutting teethinclude a straight tooth 5, which precedes in a cutting direction (i.e.,rightward in FIG. 1A) in cutting the workpiece, serving as a precedingtooth, and further, left and right set teeth 7 and 9 serving assubsequent teeth, which are subsequent to the straight tooth 5.

The straight tooth 5 is a straight saw tooth, which is not set in alateral direction, as viewed in the cutting direction of the saw blade 1with respect to the workpiece. In contrast, the left and right set teeth7 and 9 are saw teeth, which are inclined by setting in the lateraldirection, as viewed in the cutting direction (i.e., in the lateraldirection in FIG. 1B, wherein the terms “left and right” and “thelateral direction” are hereinafter used as synonyms signifying the samedirection). The height of the straight tooth 5 is designed to becomesubstantially equal to that of each of the left and right set teeth 7and 9.

The thicknesses of the straight tooth 5 and the left and right set teeth7 and 9 are equal to that of the blade base 3. Chips 11, 13 and 15 onthe tooth tips are fixed integrally with the straight tooth 5 and theleft and right set teeth 7 and 9, respectively. The chips 11, 13 and 15on the tooth tips are made of, for example, a cemented carbide steel, ahigh-speed tool steel or the like, and further, are welded byelectron-beam welding or the like.

The thickness of the chip 11 on the tooth tip formed at the straighttooth 5 is designed to be substantially equal to that of the blade base3. As a consequence, the straight tooth 5 is formed in a straight sawtooth without any inclination in the lateral direction, as shown in FIG.1B.

The chips 13 and 15 on the tooth tips formed at the left and right setteeth 7 and 9, respectively, have the tooth tips, which are formed intoa dovetail shape gradually enlarged in the lateral direction (i.e.,downward in FIG. 1B), as shown in FIG. 1B. In other words, the lateralthicknesses on the tooth tips are greater than those at the portionswelded to the left and right set teeth 7 and 9, thereby exhibiting atrapezoidal shape (i.e., the dovetail shape) in cross section.Consequently, the left and right set teeth 7 and 9 include the dovetailshaped chips 13 and 15 on the tooth tips, respectively, thus providingthe configuration of dovetail shaped set teeth.

As is understood from the above-described configuration, respective leftand right side surfaces 13F and 15F of the chips 13 and 15 on the toothtips are inclined in the vertical direction (i.e., in a width directionof the saw blade 1) in such a manner that a welding side, that is, anupper side approaches a center 3A in the thickness of the blade base 3even in a state before setting the left and right set teeth 7 and 9.Thereafter, when the left and right set teeth 7 and 9 are allowed to beset at a bending position P in the lateral direction, the left and rightset teeth 7 and 9 are inclined outward in the lateral direction in sucha manner that the tooth tips (i.e., lower portions) are separated fromthe center 3A in the thickness in the vertical direction in FIG. 1B,that is, in the width direction of the blade base 3.

Thus, even if an inclination angle when the left and right set teeth 7and 9 are set in the lateral direction is equal to that in the priorart, the inclination angle is summed up with the inclination angles ofthe side surfaces 13F and 15F of the chips 13 and 15 on the tooth tipsowing to the dovetail shape of each of the chips 13 and 15 on the toothtips, so that the inclination angle of each of the side surfaces 13F and15F of the chips 13 and 15 on the tooth tips disposed at the left andright set teeth 7 and 9 in the vertical direction becomes greater thanthe inclination angle obtained after setting the left and right setteeth 7 and 9.

Therefore, it is possible to suppress an increase in abrasion upward anddownward (i.e., in the vertical direction) even in the case wherehorizontal (i.e., lateral) abrasion occurs at outside corners 13C and15C of the chips 13 and 15 on the tooth tips disposed at the left andright set teeth 7 and 9, respectively. That is to say, it is possible tosuppress an increase in cutting resistance due to the abrasion occurringat the outside corners 13C and 15C of the chips 13 and 15 on the toothtips and an unstable state of the saw blade 1 caused by an increasedpartial force in the lateral direction, thus prolonging the lifetime ofthe saw blade and solving the above-described problems experienced bythe saw blade in the prior art.

As has been already understood, the inclination angle of the sidesurface in the vertical direction in setting becomes great by formingthe respective side surfaces 13F and 15F of the chips 13 and 15 on thetooth tips into the inclined trapezoidal shape (i.e., the dovetailshape) in advance. Thus, the dovetail shape can be formed by merelyinclining the side surface on a setting side at a predetermined angle inadvance. In other words, the side surface opposite to the side surfaceon the setting side may be formed into, for example, a vertical shape.Namely, the dovetail shape may be asymmetric between the side surface onthe setting side and the opposite side surface.

Next, a saw blade in a second preferred embodiment will be described inreference to FIGS. 2A to 2C. In the second preferred embodiment,constituent elements exhibiting the same functions as those of theconstituent elements in the above-described first preferred embodimentare designated by the same reference numerals, and therefore, duplicatedexplanation will be omitted below.

The first preferred embodiment is featured by the combination patternconsisting of the three teeth, that is, the straight tooth 5 and onepair of left and right set teeth 7 and 9. In contrast, left and rightset teeth 7 and 9 are alternately disposed, so that a combinationpattern consists of five teeth, that is, a straight tooth 5 and twopairs of left and right set teeth 7 and 9 as a whole. In this manner,with the plural pairs of left and right set teeth 7 and 9, a load to beexerted on the set teeth 7 and 9, each having the function of making awidth of a cutting groove at a workpiece W greater than a lateralthickness of the straight tooth 5, can be dispersed when the workpieceis cut, thereby suppressing respective corners 13C and 15C outside ofthe set teeth 7 and 9 from being abraded.

Furthermore, at the left and right set teeth 7 and 9 for cutting theworkpiece in order to enlarge the cutting groove at the workpiece, alaterally partial force exerted on the subsequent pair of left and rightset teeth 7 and 9 becomes smaller than that exerted on the precedingpair of left and right set teeth 7 and 9, thereby enhancing the cuttingprecision of a cutting surface (i.e., a cut face) of the workpiece.

As has been already understood, the combination pattern consisting ofthe straight tooth 5 and one pair of left and right set teeth 7 and 9may consist of the arbitrary number of each of straight teeth 5 and leftand right set teeth 7 and 9.

FIGS. 3A to 3C are views explanatory of a saw blade in a third preferredembodiment according to the invention. Constituent elements exhibitingthe same functions as those of the constituent elements in theabove-described saw blade 1 are designated by the same referencenumerals, and therefore, duplicated explanation will be omitted below.

In the third preferred embodiment, the chip 11A on a tooth tip disposedat a straight tooth 5 is formed into a trapezoidal shape (i.e., adovetail shape) in cross section, like chips 13 and 15 on tooth tipsdisposed at left and right set teeth 7 and 9. Namely, the straight tooth5 is constituted of a dovetail shaped straight tooth.

The third preferred embodiment can produce the same effect produced inthe above-described first and second preferred embodiments. When aworkpiece is cut by a saw blade 1 with application of a pressing forceto the saw blade 1 in a cutting direction (wherein the workpiece is cutdownward in FIGS. 3A and 3B), the chip 11A on the tooth tip disposed atthe straight tooth 5 is formed into the dovetail shape even in the casewhere the saw blade 1 has the tendency of slight inclination in alateral direction due to cutting resistance in the cutting direction,thereby suppressing a contact of left and right side surfaces of thechip 11A on the tooth tip with a cutting groove formed at the workpiece.

Consequently, when the saw blade 1 has the tendency of inclination inthe lateral direction, it is possible to suppress the laterally partialforce exerted on the saw blade 1 as reaction force generated by thecontact of the saw blade 1 with the workpiece, so as to suppressbreakage or bending caused by the laterally partial force exerted on thesaw blade 1. In other words, it is possible to enhance straightstability of the saw blade 1, and thus, to prolong the lifetime of thesaw blade 1. Incidentally, also in the present preferred embodiment, thenumber of each of straight teeth 5 and left and right set teeth 7 and 9may be arbitrary.

FIGS. 4A to 4C are views explanatory of a saw blade in a fourthpreferred embodiment. Constituent elements exhibiting the same functionsas those of the constituent elements in the above-described preferredembodiments are designated by the same reference numerals, andtherefore, duplicated explanation will be omitted below.

In the fourth preferred embodiment, a chip 11B on a tooth tip disposedat the straight tooth 5 is formed into a bevel-dovetail shape in crosssection, in which the chip 11B on the tooth tip is provided withinclinations 12 on both of left and right sides, by forming theinclinations 12 on both of the left and right sides at the tooth tip ofthe chip 11A on the tooth tip in the above-described third preferredembodiment. Namely, the straight tooth 5 is constituted of abevel-dovetail shape straight tooth provided with the inclinations onboth of the left and right sides at the tooth tip formed into thedovetail shape gradually enlarging in a lateral direction on the side ofthe tooth tip.

With the above-described configuration, the lateral width of the toothtip of the chip 11B on the tooth tip can be reduced by forming theinclinations 12 on both of the left and right sides at the tooth tip ofthe chip 11B on the tooth tip disposed at the straight tooth 5, therebyenhancing a biting property with respect to a workpiece. Moreover, withthe configuration in which the inclinations 12 are formed on both of theleft and right sides, a groove formed into a trapezoidal shape in crosssection is formed at a bottom of a cutting groove at the workpiece cutby the chip 11B on the tooth tip, thus restricting movement in thelateral direction so as to enhance straight stability in a cuttingdirection. In other words, the lifetime of the saw blade can beprolonged.

FIGS. 5A to 5C are views explanatory of a saw blade in a fifth preferredembodiment. Constituent elements exhibiting the same functions as thoseof the constituent elements in the above-described saw blade 1 aredesignated by the same reference numerals, and therefore, duplicatedexplanation will be omitted below.

The fifth preferred embodiment is configured such that a precedingstraight tooth 5A is additionally provided in the configuration in theabove-described third preferred embodiment (see FIGS. 3A to 3C), andfurther, that the straight tooth 5A is provided with a bevel-dovetailshaped chip 11B on a tooth tip.

When H1 designates the height of the straight tooth 5A, H2 denotes theheight of a straight tooth 5, and H3 and H4 designate the heights ofleft and right set teeth 7 and 9, respectively, the relationship isestablished as follows: H1>H2, H3, H4. Here, the relationship H2≧H3=H4is established among the respective heights H2, H3 and H4 of thestraight tooth 5 and the left and right set teeth 7 and 9.

As a consequence, with the above-described configuration, a groove iscut at a workpiece by the chip 11B on the tooth tip at the straighttooth 5A serving as a preceding tooth, before a portion remaining due toinclinations 12 at the chip 11B on the tooth tip is cut by a chip 11A ona tooth tip at the subsequent straight tooth 5, and thereafter, thelateral outside of a groove cut by the chip 11A on the tooth tip is cutby the left and right set teeth 7 and 9. Thus, a cutting groove is cutin such a manner as to be enlarged as a whole.

That is to say, with the above-described configuration, a load can bedispersed to the chips 11B, 11A, 15 and 13 on the tooth tips in cuttingthe workpiece, and further, cutting dust produced during the cuttingwork can be fined. Thus, it is possible to alleviate cutting resistanceto be exerted on each of the saw teeth and enhance straight stability ofthe saw blade, so as to solve the above-described problems experiencedin the prior art. Incidentally, the relationship H2≦H3, H4 may beestablished among the respective heights H2, H3 and H4 of the straighttooth 5 and the left and right set teeth 7 and 9.

FIGS. 6A to 6C are views explanatory of a saw blade in a sixth preferredembodiment. Constituent elements exhibiting the same functions as thoseof the constituent elements in the above-described preferred embodimentsare designated by the same reference numerals, and therefore, duplicatedexplanation will be omitted below.

In the sixth preferred embodiment, the relationship H1>H2>H3, H4 isestablished among the respective heights H1, H2, H3 and H4 of thestraight teeth 5A and 5 and the left and right set teeth 7 and 9.

Consequently, the above-described configuration can produce the sameeffect produced in the fifth preferred embodiment. Moreover, insidecorners 13I and 15I at chips 13 and 15 on tooth tips at the left andright set teeth 7 and 9 (i.e., corners on a side opposite to outsidecorners 13C and 15C, respectively) are located inside of a movementtrace depicted when chips 11A and 11B on tooth tips at the straightteeth 5 and 5A are moved in a cutting direction.

Thus, the chips 11B and 11A on the tooth tips at the straight teeth 5Aand 5 precede in a cutting direction when a workpiece is cut. As aconsequence, it is possible to avoid a load from being concentrated onthe inside corners 13I and 15I at the chips 13 and 15 on the tooth tipsat the left and right set teeth 7 and 9 when the workpiece is cut, andfurther, to prevent any chipping at the corners 13I and 15I. A badbalance in a lateral direction is tended to induce breakage or bendingin the case where the inside corners 13I and 15I at the chips 13 and 15on the tooth tips at the left and right set teeth 7 and 9 non-uniformlyproject. However, such a problem can be avoided by the above-describedconfiguration.

FIGS. 7A to 7C are views explanatory of a saw blade in a seventhpreferred embodiment. Constituent elements exhibiting the same functionsas those of the constituent elements in the above-described preferredembodiments are designated by the same reference numerals, andtherefore, duplicated explanation will be omitted below.

The seventh preferred embodiment is configured such that inside corners13I and 15I at chips 13 and 15 on tooth tips at left and right set teeth7 and 9 are located on the back side of a chip 11 on a tooth tip at astraight tooth 5 (i.e., within the movement trace of the chip 11 on thetooth tip) by making the height H2 of the straight tooth 5 greater thanthe heights H3 and H5 of the left and right set teeth 7 and 9 in theabove-described third preferred embodiment (see FIGS. 3A to 3C), asshown in FIG. 7B. Consequently, the configuration can produce the sameeffect produced in the above-described preferred embodiment.

In the preferred embodiment shown in FIGS. 7A to 7C, the chip 11 on thetooth tip at the straight tooth 5 may be configured in a chip 11A or 11Bon a tooth tip shown in FIGS. 8A and 8B, respectively. Otherwise, in aconfiguration in which the heights of the straight tooth 5 and the leftand right set teeth 7 and 9 are substantially equal to each other, asshown in FIG. 8C, inclined surfaces 13B and 15B may be formed byremoving the inside corners at the chips 13 and 15 on the tooth tips atthe left and right set teeth 7 and 9.

This configuration also can produce the same effect produced in theabove-described preferred embodiments.

FIGS. 9A and 9B are conceptual and schematic views explanatory of astraight tooth and left and right set teeth in a saw blade 1 inmodifications. That is to say, in the present preferred embodiment, thethickness of a joint portion 17A of a dovetail shaped chip 17 on a toothtip is made to be smaller than those of a straight tooth 5 and left andright set teeth 7 and 9 in the saw blade 1.

With the above-described configuration, an inclination angle θ1 in avertical direction of left and right side surfaces 17C at the chip 17 onthe tooth tip can be more increased in the case where a thickness 17Band a height on a tip side of the chip 17 on the tooth tip are constant.As a consequence, an inclination angle θ2 at the side surface 17C at thechip 17 on the tooth tip at the time of a setting work becomes equal tothe sum of the inclination angle θ1 before the setting work and asetting angle at the time of the setting work, as shown in FIG. 9B,thereby providing the inclination angle greater than that in theabove-described preferred embodiment. Thus, it is possible to moreeffectively prolong the lifetime of the saw blade 1.

Incidentally, it is to be understood that the invention should not belimited to the above-described preferred embodiments, and therefore,that the invention can be carried out in other modes with appropriatevariations and alterations.

The entire contents disclosed in Japanese Patent Application No.2002-297928 (filed on Oct. 10, 2002) are encompassed in thespecification of the application of the invention by reference.

1. A saw blade provided with numerous cutting teeth for cutting aworkpiece at appropriate pitches, the saw blade comprising: left andright set teeth, which are set in a lateral direction, as viewed in acutting direction of the cutting teeth; wherein each of the left andright set teeth is a dovetail shaped set tooth having a tooth tip whichis gradually enlarged in the lateral direction.
 2. A saw blade accordingto claim 1, further comprising: a straight tooth, which is not set inthe lateral direction, as viewed in the cutting direction of the cuttingteeth; wherein the straight tooth including a dovetail shaped straighttooth having a tooth tip which is gradually enlarged in the lateraldirection.
 3. A saw blade according to claim 2, wherein a height of eachof the left and right set teeth is smaller than or substantially equalto that of the straight tooth.
 4. A saw blade according to claim 2,wherein an inclination is formed at an inside corner on a tooth tip sideof each of the left and right set teeth.
 5. A saw blade according toclaim 2, wherein the cutting teeth are configured by joining a dovetailshaped chip to the tip end of the tooth in a blade base; and wherein thethickness of the chip at the joint portion is made to be smaller thanthat of the tip end of the tooth.
 6. A saw blade according to claim 1,further comprising: a straight tooth, which is not set in the lateraldirection, as viewed in the cutting direction of the cutting teeth;wherein the straight tooth including a bevel-dovetail shaped straighttooth having inclinations at both of left and right ends of a tooth tipwhich is gradually enlarged in the lateral direction.
 7. A saw bladeaccording to claim 6, wherein a height of each of the left and right setteeth is smaller than or substantially equal to that of the straighttooth.
 8. A saw blade according to claim 6, wherein the inclination isformed at an inside corner on a tooth tip side of each of the left andright set teeth.
 9. A saw blade according to claim 6, wherein thecutting teeth are configured by joining a dovetail shaped chip to thetip end of the tooth in a blade base; and wherein the thickness of thechip at the joint portion is made to be smaller than that of the tip endof the tooth.
 10. A saw blade according to claim 1, further comprising:a straight tooth, which is not set in the lateral direction, as viewedin the cutting direction of the cutting teeth; wherein in theabove-described configuration, the straight tooth includes: a dovetailshaped straight tooth having a tooth tip which is gradually enlarged inthe lateral direction; and a bevel-dovetail shaped straight tooth havinginclinations at both of left and right ends of a tooth tip which isgradually enlarged in the lateral direction; and wherein a height of thedovetail shaped straight tooth is smaller than or substantially equal tothat of the bevel-dovetail shaped straight tooth.
 11. A saw bladeaccording to claim 10, wherein a height of each of the left and rightset teeth is smaller than or substantially equal to that of the straighttooth.
 12. A saw blade according to claim 10, wherein the inclination isformed at an inside corner on a tooth tip side of each of the left andright set teeth.
 13. A saw blade according to claim 10, wherein thecutting teeth are configured by joining a dovetail shaped chip to thetip end of the tooth in a blade base; and wherein the thickness of thechip at the joint portion is made to be smaller than that of the tip endof the tooth.